Logic of copying variants between files

I have a master variant component in a parent file. I would like to keep that as a base for satellite themed components in a different libraries so they inherit parent updates. Below are 3 options. Questions at 2 & 3.

  1. Add the instances, turn them into components (nesting parent instance), and create new variant. This works but it seems I have to rename everything.

  2. I can copy the entire master from the parent file and paste it into the new satellite file. Doesn’t seem to work - I don’t inherit changes from parent. Why is this?

  3. I can copy the entire master from another satellite that has done number one (parent component is nested) and it seems to work, but why?